1. Field of the Invention
The present invention relates generally to cementing multi-lateral wells, and more particularly, to methods of cementing such wells whereby the cement sets into a high strength impact resistant solid mass.
2. Description of the Prior Art
The development of wells including one or more laterals to increase production has recently taken place. Such multilateral wells include vertical or deviated (including horizontal) principal well bores having one or more ancillary laterally extending well bores connected thereto. More recently, drilling and completion equipment has been developed which allows multiple laterals to be drilled from a principal cased and cemented well bore. Each of the lateral well bores can include a liner cemented therein which is tied into the principal well bore. The lateral well bores of a multilateral well can be drilled into predetermined producing formations or zones at any time in the productive life cycle of the well, and the lateral-well bores also can be vertical or deviated (including horizontal).
While such multi-lateral wells have been successfully drilled and operated, a problem in the operation involves the cement slurry utilized to cement the casing and liners in the well. The casing and liners are cemented in the principal and lateral well bores, respectively, by introducing cement slurries in the annular clearances between the walls of the well bores and the casing and liners. The cement slurries set into hard masses to thereby support the casing and liners in the well bores and to seal the annuluses whereby fluid flow through the annuluses between formations and zones is prevented. Heretofore, conventional well cement slurries have been utilized which set into brittle solid masses. The brittle set cement can not withstand impacts and shocks subsequently generated by drilling and other well operations carried out in the multiple laterals without shattering. Once the set cement is shattered, it allows leakage of fluid through at least portions of the well bores which can be highly detrimental.
Thus, there is a need for improved methods of cementing multi-lateral wells whereby the set cement has a high strength and impact resistance and withstands shocks and impacts without shattering.